1. Field of the Invention
The present invention relates to an isolating device for a water chamber in a steam generator for a nuclear reactor.
2. Description of the Prior Art
In a pressurized water type nuclear reactor, as shown in FIG. 8, a nuclear reactor vessel (01), a water chamber (02a) in a steam generator (02) and a coolant pump (03) are mutually connected with one another by means of coolant pipes (04) to form a coolant circulating loop.
And in an atomic power plant, for the purpose of inspection for confirming safety of the component instruments and the systems as well as replacement of the fuels, operation of the nuclear reactor is interrupted nearly once a year.
Upon the inspection and fuel replacement, tasks relating to the nuclear reactor such as opening of a nuclear reactor vessel, extraction of fuels, inspection of a reactor core, charging of fuels, reassembly of a nuclear reactor, etc. are carried out in shielding water after the nuclear reactor vessel (01), a nuclear reactor cavity (05) and the like have been filled with shielding water. Then, inspection of thin tubes in the steam generator to be effected at that time is necessitated to be carried out under the condition that the water has been extracted, but the tasks relating to the nuclear reactor and the inspection of the thin tubes in the steam generator cannot be performed simultaneously, because the shielding water is filled during the work relating to the nuclear reactor. Accordingly, the time required for the inspection would become long, and this would limit improvement of the rate of operation of the atomic power plant. The present invention has been worked out in view of the above-mentioned background in the art.